7 files changed, 22 insertions, 40 deletions

diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c
index 7e8d3bc80af6..50542efe45fb 100644
--- a/arch/x86/xen/enlighten.c
+++ b/arch/x86/xen/enlighten.c
@@ -1194,7 +1194,7 @@ asmlinkage void __init xen_start_kernel(void)
         per_cpu(xen_vcpu, 0) = &HYPERVISOR_shared_info->vcpu_info[0];
 
         local_irq_disable();
-        early_boot_irqs_off();
+        early_boot_irqs_disabled = true;
 
         memblock_init();
 
diff --git a/include/linux/kernel.h b/include/linux/kernel.h
index 5a9d9059520b..d07d8057e440 100644
--- a/include/linux/kernel.h
+++ b/include/linux/kernel.h
@@ -243,6 +243,8 @@ extern int test_taint(unsigned flag);
 extern unsigned long get_taint(void);
 extern int root_mountflags;
 
+extern bool early_boot_irqs_disabled;
+
 /* Values used for system_state */
 extern enum system_states {
         SYSTEM_BOOTING,
diff --git a/include/linux/lockdep.h b/include/linux/lockdep.h
index 71c09b26c759..f638fd78d106 100644
--- a/include/linux/lockdep.h
+++ b/include/linux/lockdep.h
@@ -436,16 +436,8 @@ do {								\
 #endif /* CONFIG_LOCKDEP */
 
 #ifdef CONFIG_TRACE_IRQFLAGS
-extern void early_boot_irqs_off(void);
-extern void early_boot_irqs_on(void);
 extern void print_irqtrace_events(struct task_struct *curr);
 #else
-static inline void early_boot_irqs_off(void)
-{
-}
-static inline void early_boot_irqs_on(void)
-{
-}
 static inline void print_irqtrace_events(struct task_struct *curr)
 {
 }
diff --git a/init/main.c b/init/main.c
index 00799c1d4628..33c37c379e96 100644
--- a/init/main.c
+++ b/init/main.c
@@ -96,6 +96,15 @@ static inline void mark_rodata_ro(void) { }
 extern void tc_init(void);
 #endif
 
+/*
+ * Debug helper: via this flag we know that we are in 'early bootup code'
+ * where only the boot processor is running with IRQ disabled.  This means
+ * two things - IRQ must not be enabled before the flag is cleared and some
+ * operations which are not allowed with IRQ disabled are allowed while the
+ * flag is set.
+ */
+bool early_boot_irqs_disabled __read_mostly;
+
 enum system_states system_state __read_mostly;
 EXPORT_SYMBOL(system_state);
 
@@ -554,7 +563,7 @@ asmlinkage void __init start_kernel(void)
         cgroup_init_early();
 
         local_irq_disable();
-        early_boot_irqs_off();
+        early_boot_irqs_disabled = true;
 
 /*
  * Interrupts are still disabled. Do necessary setups, then
@@ -621,7 +630,7 @@ asmlinkage void __init start_kernel(void)
         if (!irqs_disabled())
                 printk(KERN_CRIT "start_kernel(): bug: interrupts were "
                                  "enabled early\n");
-        early_boot_irqs_on();
+        early_boot_irqs_disabled = false;
         local_irq_enable();
 
         /* Interrupts are enabled now so all GFP allocations are safe. */
diff --git a/kernel/lockdep.c b/kernel/lockdep.c
index 42ba65dff7d9..0d2058da80f5 100644
--- a/kernel/lockdep.c
+++ b/kernel/lockdep.c
@@ -2292,22 +2292,6 @@ mark_held_locks(struct task_struct *curr, enum mark_type mark)
 }
 
 /*
- * Debugging helper: via this flag we know that we are in
- * 'early bootup code', and will warn about any invalid irqs-on event:
- */
-static int early_boot_irqs_enabled;
-
-void early_boot_irqs_off(void)
-{
-        early_boot_irqs_enabled = 0;
-}
-
-void early_boot_irqs_on(void)
-{
-        early_boot_irqs_enabled = 1;
-}
-
-/*
  * Hardirqs will be enabled:
  */
 void trace_hardirqs_on_caller(unsigned long ip)
@@ -2319,7 +2303,7 @@ void trace_hardirqs_on_caller(unsigned long ip)
         if (unlikely(!debug_locks || current->lockdep_recursion))
                 return;
 
-        if (DEBUG_LOCKS_WARN_ON(unlikely(!early_boot_irqs_enabled)))
+        if (DEBUG_LOCKS_WARN_ON(unlikely(early_boot_irqs_disabled)))
                 return;
 
         if (unlikely(curr->hardirqs_enabled)) {
diff --git a/kernel/smp.c b/kernel/smp.c
index 2fe66f7c617a..9910744f0856 100644
--- a/kernel/smp.c
+++ b/kernel/smp.c
@@ -459,7 +459,7 @@ void smp_call_function_many(const struct cpumask *mask,
          * can't happen.
          */
         WARN_ON_ONCE(cpu_online(this_cpu) && irqs_disabled()
-                     && !oops_in_progress);
+                     && !oops_in_progress && !early_boot_irqs_disabled);
 
         /* So, what's a CPU they want? Ignoring this one. */
         cpu = cpumask_first_and(mask, cpu_online_mask);
@@ -572,17 +572,20 @@ void ipi_call_unlock_irq(void)
 #endif /* USE_GENERIC_SMP_HELPERS */
 
 /*
- * Call a function on all processors
+ * Call a function on all processors.  May be used during early boot while
+ * early_boot_irqs_disabled is set.  Use local_irq_save/restore() instead
+ * of local_irq_disable/enable().
  */
 int on_each_cpu(void (*func) (void *info), void *info, int wait)
 {
+        unsigned long flags;
         int ret = 0;
 
         preempt_disable();
         ret = smp_call_function(func, info, wait);
-        local_irq_disable();
+        local_irq_save(flags);
         func(info);
-        local_irq_enable();
+        local_irq_restore(flags);
         preempt_enable();
         return ret;
 }
diff --git a/kernel/trace/trace_irqsoff.c b/kernel/trace/trace_irqsoff.c
index 5cf8c602b880..92b6e1e12d98 100644
--- a/kernel/trace/trace_irqsoff.c
+++ b/kernel/trace/trace_irqsoff.c
@@ -453,14 +453,6 @@ void time_hardirqs_off(unsigned long a0, unsigned long a1)
  * Stubs:
  */
 
-void early_boot_irqs_off(void)
-{
-}
-
-void early_boot_irqs_on(void)
-{
-}
-
 void trace_softirqs_on(unsigned long ip)
 {
 }